Why do the Chinese have such long showers

My province is in the grip of drought and agricultural production is beginning to be seriously affected.  The uni administration has asked students to contribute ideas on how to conserve water and some students in turn asked my wife for advice.  'Why don't you institute a rule of three minute showers' she offers.  'Oh no, we couldn't do that' was the reply.  'No-one would like that'.  On further questioning the students estimate the average shower to be about half an hour, with some students staying under for about an hour.  Needless to say, the students do not pay directly for water.  (My suggestion was 'make them pay directly for water'.)  What do poddies think?